For electronics industry, the Moore's law only forecasts for an increased packaging density of gates for electronic devices, and nothing about reducing power dissipation per gate. Even if lots of effort is placed in reducing per-gate consumption, it is not done in the same rate for the packaging density. The consequence is that the power dissipation and the cooling need per volume electronic unit increase substantially.
The industry faces numerous problems with the cooling of electronics such as Radio Base Stations, Network Servers, Work stations, and High-power rectifiers etc. Today's electronics is usually cooled with forced air or water-cooled solutions. The disadvantages with forced cooling are numerous such as (a) an extra heat exchanger is needed since outdoor air can not be used directly i.e. to avoid dust, humidity etc.; (b) air channels take extra volume and add costs due to increased mechanical setups; (c) power consuming internal air fans; (d) dummy modules are required for controlling the air flow when systems are not fully equipped and (e) dimensioning of cooling capacity per module is directly connected to volume. That means that small power-consuming modules must have higher volume in order get enough cooling. The effect is also the same in the other direction with low-power, but volume demanding modules. These modules get more cooling capacity allocated to them than they actually need.
In U.S. Pat. No. 4,793,405-A, a condenser is connected at the top to a riser and at the bottom to a downpipe. Below the condenser, a vertically disposed, plate-shaped element is arranged, there being formed along the two vertical edges of this element the conduits and, between these, several evaporators, separated from one another by perforations, for transferring the heat loss of the electrical elements to a liquid. Each of the evaporators is connected at one end at the top with the riser and at the opposite end at the bottom with the downpipe. The condenser, the conduits, and the evaporators constitute a unit sealed in a pressure-proof fashion which is filled with the liquid, that can be evaporated in the evaporators by the heat loss and can be condensed in the condenser, to such an extent that the liquid volume lies above the uppermost evaporator and below the condenser or in the lower portion of the latter. The element forms the rear wall of an electronic equipment rack, each evaporator being in heat-conductive connection with the electrical elements arranged in a tier of the rack.
In US2006005980A1, a thermal energy management system is provided having a heat spreading device that is operatively engaged with at least one semiconductor chip and a thermal bus operatively engaged with the heat spreading device so as to transport thermal energy from the heat spreading device to a heat sink. The heat spreading device includes a heat pipe and the thermal bus includes a loop thermosyphon. A second thermal bus may be operatively engaged with the first-thermal bus so as to transport thermal energy from the first thermal bus to a heat sink. The second thermal bus may also include a loop thermosyphon. A method of managing thermal energy in an electronic system is also provided that includes spreading thermal energy generated by one or more devices over a surface that is relatively larger than the devices, thermally coupling an evaporator portion of a loop thermosyphon to the surface, and thermally coupling a condensing portion of the loop thermosyphon to a thermal energy sink, e.g., a second loop thermosyphon, convection fin, or cold plate.
Thus the major problems with above mentioned prior art is that the cooling systems are (a) expensive infrastructure; (b) difficult plumbing on system and module level and (c) difficult connector-to-module connections that take time to assemble and also are a potential leakage source of cooling media such as fluorohydrocarbons etc.